For a very simple basic T-Shirt Quilt I use a finished 12” block with sashing and cornerstones. The cut size is 12 ½” unfinished and I find it easiest to use a quilters square ruler of that size as a template. I do use fusible interfacing. I go for a light weight. I think Pellon is the brand. Unlike many, I stabilize my blocks AFTER I cut them out. I find I have much less waste with the stabilizer that way.
To make a queen size quilt like the one I pictured here
http://www.quiltingboard.com/t-47094-1.htm you need a total of 48 imprints. So if your shirts have a big imprint on front AND back you need a total of 24 shirts. Many shirts only have a small breast imprint on the front. Like on a pocket T.
First inspect the T-shirts. If they are screen print ink imprints you are fine but some shirts are really cheapo and use an iron on imprint instead of screen print. You can tell the difference because the iron on stuff feels kind of rubbery. You can not use the iron on!
Cut the shirts apart along the sides so you have a fairly flat imprint to cut out. I save the scraps and tear them into strips and use them to tie up tomato plants!
I cut out a bunch of 12 1/2" square pieces of interfacing. Because it only around 20" wide you will have a bunch of left overs. I use those as well simply butting up two pieces to cover the squares on the back. I cut the scraps down to fit. If they overlap a bit that is fine.
I use my 12 1/2" square ruler and center the imprint and cut it out. Then iron on my interfacing immediately before the t-shirt knit has a chance to start curling up. When applying the interface you MUST use a press cloth (instructions will tell you that, you need to mist it with water). For ironing as you assemble you must also use a press cloth but no need to dampen it. The heat from the iron will melt the ink in the screen prints if applied directly (ask me how I know)
For T's that only have a small breast imprint I cut those out 3" unfinished (to finish at 2 1/2" and use them as my cornerstones. If you don't have enough of those you can use any other fabric. I have used scraps of T's with interfacing applied, bandanas, blue jeans, or any cotton fabric. I have even made small pinwheels.
Cut sashing strips 12.5 x 3. You will need 49 of these for a 4 x 5 setting.
With this setting plus the sashing your inner part of the quilt should measure 61" wide x 76" long (unfinished).
When assembling I lay out my blocks until I am happy. Sew a cornerstone to each end of 15 of your sashing strips. Press seams towards sashing strip. Start with your first row. Sew a plain sashing strip to top and bottom of all 4 shirts in your first row. Press seams towards sashing strip. Then sew a cornerstoned sashing strip to ONLY THE RIGHT SIDE of each block except the last one in the row. For that one sew a cornerstone sash to each side. Press seams toward sashing strip. Now sew all your blocks together. Press seams to one side. You may wish to alternate the way you press for ease of sewing rows together. I usually don’t because I end up forgetting or getting some in the wrong direction. As long as you pin well when joining the rows you should be fine. You are done with row one!
Row two sew a PLAIN sashing strip to ONLY THE RIGHT SIDE of each block except the last. Sew to both sides on the last. Press. Sew these blocks together. Then line them up with completed row one. Line up seams, pin well and join the rows. Congratulations you now have two rows completed.
Repeat instructions for rows 1 and 2 on rows 3 and 4. Finally for row 5, complete as row one. Sew all these rows together and TA-DAH you have completed your center. If you work on it for an hour or so each evening and do a mega sew on a weekend you can have the center completed in one week easily.
From here you decide if you want to add an inner border or not. I usually do and did in the pictured quilt. I cut strips 1 1/2 wide and piece them together for the right length for the sides, top and bottom. Remember to measure from the center of your quilt. Ease in any fullness. I always press out towards the border strip.
OPTIONAL: Some T's have wide narrow imprints. I will usually cut these out at 6.5" x 18" approximately. You may want to cut them wider and cut them down later once you measure for your borders. I will sew two of these together to get my 12 1/2" height but the length is longer to capture the whole imprint and to add interest to the border pieces.
Otherwise you can cut your border blocks all the same size and follow below instructions
I simply sew together the remaining T-blocks for my outer border inserting a strip on the sides of blocks if necessary to make it the appropriate length. Again, make sure you measure the center of your quilt and use that measurement and ease in any fullness when you go to attach it to your quilt. I try to center the any narrow or odd sized blocks on each side for visual interest. Based on my shirt counts and having a couple of wider blocks I end up with 6 blocks butted together for each side and 8 on top and bottom.
Sandwich up and quilt as desired. I usually use fat bat and tie them with three strands of embroidery floss. I will also longarm them. But I feel they are too heavy and difficult to manipulate for domestic machine quilting. You may feel differently.
They are super easy. I use a universal, sharp or topstitch needle when piecing them together. Some people use a ballpoint but because I am joining the knit to a quilting cotton, I prefer to not use a ballpoint.
PM me any time if you get stuck.